Abstract: In CCS hydropower construction in Ecuador, aiming at the Mexican supervisor's requirement of adopting Bierbaumer theory to calculate tunnel's rock pressure and using American code to guide the design process, according to the parameters of different rock type, we make a differences analysis on surrounding rock pressure calculation methods, including the Rock Pillar method, Terzaghi theory, M. M. Promojiyfakonov theory, Bierbaumer theory and domestic standards etc.. The analysis show the first three methods do not comply with the requirements of the CCS project. We propose to make a correction to the rock pressure calculation method based on the Bierbaumer theory by referring to domestic standards. In the design process, we use American Standard to conduct structural design in seismic and non-seismic case. At the same time, SAP2000 and ANSYS FEM software are applied to analyze the special parts of tailrace tunnel, such as corner part of large section lining, spandrel, weakened wall structure due to buried pipes, thin wall of U section structures. The analysis results show that the structural design meets the foreign standards' requirements, and it is of great guiding significance for the design and research of similar foreign projects.